Metropolis Castle, locally known as Metropolis Kalesi, lies on a hillside between the villages of Özbey and Yeniköy, in the province of Izmir in Turkey.
Metropolis Castle was built by the Byzantines on top of the remains of the ancient Greek city of Metropolis. It was built as a precaution against the Arab raids into Byzantine territory. The old acropolis of the Greek city was strengthened and used as the upper bailey. Two curtain walls descended down the hill from the upper bailey, ending in 2 square towers with a curtain wall between them, forming a lower bailey. The entrance gate to the castle was right on the stage of the old bouleuterion (council house) of the old Greek city.
In the 14th century the area was conquered by Gazi Mehmed Bey, founder of the Beylik of Aydın. The remaining population of Metropolis moved away to nearby Torbalı.
The castle was built out of rubble work masonry but also used building materials quarried from the ruins of the Greek city. Some years ago even an almost complete marble statue was found and carefully removed out of the southern curtain wall.
The remains of the castle itself are not very impressive but the way it is built over the ancient Greek buildings is. The 2 square corner towers can not be entered. The remains of the ancient Greek city itself are also very interesting. The area of the old city, containing the castle, is an archeological park. It can be entered during the daytime, free of charge.